Atrial fibrillation is a common disorder and can be associated with significant morbidity and mortality, including embolic stroke and symptoms related to loss of atrial mechanical function and atrioventricular synchrony. Current treatment for atrial fibrillation includes: medication, cardioversion (external and internal), catheter ablation of the bundle of His, surgical maze, and most recently, attempts to create the functional equivalent of surgical maze by transcatheter ablation. At present, there is a clear lack of tools to assist the clinician in determining which of these treatment strategies is best suited for a given patient. This problem is likely to be compounded as new treatments continue to emerge. In addition to the immediate need for optimizing patient treatment, there is a longer-term need for a better understanding of the electrophysiological mechanisms responsible for atrial fibrillation. The goal of this project is development of a new class of metrics for quantifying the spatiotemporal structure of electrical propagation during atrial fibrillation. These metrics, derived from endocardial electrograms, are based on representing the electrogram data as a sequence of activation events rather than a set of continuous waveforms. PROPOSED COMMERCIAL APPLICATIONS: Creare will develop a new technique for evaluating patients with atrial fibrillation intended for use in the cardiac electrophysiology laboratory. The technique will provide the clinician with a significant new capability and be of great commercial interest to vendors of data acquisition systems for use in the cardiac electrophysiology laboratory.